The Middle East’s biggest plane-leasing firm wrote off half-a-billion dollars for aircraft stranded in Russia, after the Kremlin issued a law preventing foreign-owned jets from leaving the country without state permission.

Dubai Aerospace Enterprise booked a $538 million write-off for planes with airlines in Russia, it said in a statement on Friday. The company also filed insurance claims of $1 billion, and said this figure may rise.

Aircraft lessors have been caught up in the international response to Russia’s invasion of Ukraine. The Kremlin has blocked the repossession of planes as required by sanctions, stranding roughly 400 jets that had been leased to Russian companies.

Dubai Aerospace Enterprise caters to over 170 airline customers in over 65 countries. Its leasing division manages a fleet of about 425 Airbus SE, ATR and Boeing Co. aircraft, according to information on its website.